Economic fundamentals and earnings growth cannot support the huge climb in U.S. equities projected by noted bull Laszlo Birinyi, two market watchers said Tuesday.
"Everyone is hard put to see real economic growth in the U.S.," said Rich Weiss, senior portfolio manager at American Century Investments, in a CNBC "Power Lunch" interview.
His comments come after Birinyi contended that the could climb to 3,200—a more-than-50 percent increase from its current level—by 2017. The S&P was trading slightly lower on Tuesday and has climbed about 1.6 percent this year.
"What we're really trying to tell people is stay with it. Don't let the bad news shake you out," he said on CNBC's "Fast Money: Halftime Report."
Read MoreBirinyi: S&P can hit 3,200 by 2017
Weiss contended that Birinyi's projection came "five years late." He noted that annual gross domestic product growth that may not top 3 percent—combined with the Federal Reserve potentially tightening monetary policy—would not support a stock market that strong.
Mark Luschini, chief investment strategist at Janney Capital Management, also expressed doubts that markets could mount a climb that high.
"I don't see it coming through earnings growth," he said Tuesday on "Power Lunch."
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He noted that the market could better be defined as sideways than up or down.